1. Field of the Invention
The present invention generally concerns the control of downhole apparatus in petroleum production wells for accomplishing a wide variety of control functions, without necessitating the presence of control cables, conductors in the well, or mechanical manipulators. The present invention broadly concerns a system or method that is employed to relay information from the surface to a downhole tool or well apparatus and to likewise relay information from downhole apparatus to the surface. More particularly, the present invention concerns the provision of apparatus located in the downhole environment which is operational responsive to predetermined instructions to perform predetermined well control functions, and one or more operation instruction devices which are provided with desired instructions and are moved through well tubing, such as coiled tubing, from the surface to close proximity with the downhole well control apparatus for transmission of the well control instructions to an antenna or other detector.
2. Description of the Related Art
Historically, one of the limiting factors of coiled tubing as a conveyance mechanism has been the lack of effective telemetry between the surface and the downhole tools attached to the coiled tubing. An example of a tool string that may be deployed on coiled tubing is described in U.S. Pat. No. 5,350,018, which is incorporated herein by reference. The tool string of the '018 patent communicates with the surface by means of an electrical conductor cable deployed in the coiled tubing. Some tools send go/no-go type data from a downhole tool to the surface by means of pressure pulses. Other tools are designed to be operated using push/pull techniques requiring highly skilled and experienced operators and often produce inconsistent results. Hence, a truly effective way to send information or instructions from the surface to a downhole coiled tubing tool has not yet been implemented. Since many wells have deviated or horizontal sections or multilateral branch bores, the use of coiled tubing is in many cases preferred for deploying and energizing straddle packers, casing perforators, and other well completion, production and treating tools, thus increasing the importance of effective communication between the surface and downhole tools.